GrimAndBearIt writes: NASA's Curiosity rover is poised to settle years of debate on the question of atmospheric methane on Mars, which would be a sign of microbial life. With parts per trillion sensitivity, it's not so much a question of whether the rover will be able to smell trace amounts of methane, but rather a question of how much.

NASA has announced that Grotzinger’s team will discuss atmospheric measurements at a briefing on 2 November. If the rover has detected methane at sufficiently high concentration, or exhibiting temporal variations of the kind that suggests microbial activity, then it will surely motivate a desire to identify and map the sources.